1. Field of the Invention
This invention relates generally to closures for containers and, more particularly, to a pilfer-proof closure adapted for use with the conventional screw threads of a standard container, such as a bottle.
2. Description of the Prior Art
The prior art is replete with various types of closures for containers having means to indicate whether the closure has been tampered with. Such pilfer-proof closures may comprise a body having an upper threaded portion and a lower depending skirt portion which protects a locking ring that is connected by frangible means to the main body of the closure. However, the locking rings of the prior art pilfer-proof closures generally abut against a specially formed flange on the neck of a container and cannot be adapted for use with the conventional necks on standard containers. For example, U.S. Pat. No. 3,737,064, issued to the applicant, shows a locking ring which must abut against a protruding annular flange on the neck of the container, and hence is of no value for standard containers.
In addition, the locking elements of many of the prior art closures require relatively complex die forming equipment in order to form the various flanges needed. Generally, once the flanges have been formed, the dies must be collapsible in order to release the closure from the forming mandrel as taught by U.S. Pat. No. 3,329,295 to Fields. Still other of the prior art closures must be completely broken to indicate tampering and cannot thereafter be reused to close the container.